The study, reviewed Monday by the Portland Press Herald, concluded that the highest exposure level averaged over time is 4.6 percent of the FCC limit. The agency regulates equipment that broadcasts radio-frequency signals.

The report was done by True North Associates and C2 Systems and overseen by Maine's Office of the Public Advocate.

The results, however, provide little comfort to people who complain that the meters are hurting their health, causing symptoms that include headaches and fatigue. They say the findings were expected and are meaningless.

"The question is, are there biological effects at levels lower than the FCC guidelines " said Ed Friedman, the Bowdoinham man who led a court suit last year on behalf of smart-meter opponents. "Our evidence submitted proves that beyond a shadow of a doubt."
Friedman said the testimony he has received from international experts and a survey of affected people will document health effects from smart meters. That evidence has been submitted to the Maine Public Utilities Commission, for an ongoing case meant to resolve health and safety questions about the new meters.

But to CMP, the study confirms the utility's position that smart meters are safe and that opponents actually have a wider target that includes all wireless technology, including baby monitors and garage door openers.

"This is not a case about smart meters," said John Carroll, a CMP spokesman. "It's a case about people who think radio waves and radio technology are making them sick."
The study is part of a case that's slowly progressing at the PUC. In 2010, regulators approved plans for CMP to replace old-style analog electric meters for its 615,000 customers with digital smart meters. The $200 million project received half of its funding from federal stimulus dollars.

The commission thought it had addressed health and safety questions at the time, when the issue was first raised. But last summer, the Maine Supreme Judicial Court sided with opponents of the new-technology meters, who argued that regulators ignored their legal mandate to ensure the delivery of "safe, reasonable and adequate" utility service.

Two weeks later, commissioners voted to investigate the wireless devices.

CMP argued that the scope of the review should be narrow and focused on the legal requirement. But opponents succeeded in pushing for a fully litigated case, which involves reams of written and oral testimony from expert witnesses and aggrieved residents, rebuttals and discovery, hearings and, finally, deliberations.

Those hearings have been set for May, with deliberations later this year.

Informing their decision will be the hiring by Richard Davies, the state's public advocate, of an independent expert to test the levels of radio-frequency output at actual homes.

"There's a sense that opponents don't trust CMP to give them the facts," Davies said.

The study was conducted in January, in Portland and Augusta. It was done over a series of days in three homes. Consultants also measured emissions from other parts of the network that relay data into the customer billing and information systems. The specific locations and dates weren't disclosed to CMP.

Many utilities around the world are moving to smart meters, which can give customers online information about their energy-use patterns and allow power companies to pinpoint problems during outages. The meters also transmit usage data to the utilities, virtually eliminating the need for meter readers.

But a small, vocal minority of customers isn't interested in those features. They say the radio-frequency radiation emitted by the wireless meters can cause health problems that include sleep loss and dizziness, and invade privacy because of the information they collect. In an effort to address those concerns, the PUC allows customers to opt out of having the meters, if they pay a $12 monthly fee to cover the cost of alternative equipment and meter readers. Roughly 8,300 customers have made that choice.

A key benchmark of the study is the radio-frequency limit that the FCC defines as Maximum Permissible Exposure for a person. At the frequency used by CMP's smart meters, the limit for the general public is one milliwatt per square centimeter.

Measuring these emissions from smart meters was complicated, True North Associates said in its report. The data sent from individual meters to the network takes place in short bursts that last only a few milliseconds. The majority of the activity happens between midnight and 1:30 a.m.

The study estimated that roughly 99 percent of CMP's meters broadcast up to 8.6 seconds a day. One meter, which relays information from several other meters, had a total broadcast time of 3.5 minutes a day.

Friedman said these findings were expected. Opponents declined an invitation to participate in the study because they simply feel the FCC limits don't address the real problems. For reasons that are not clear, Friedman said, smart meters seem to sensitize some people to problems with other wireless devices, such as routers for home computers. That's why more study is needed on the impact of exposing people to radio-frequency waves, he said.

If that's the issue, responded Carroll at CMP, smart-meter opponents should take their case to cellphone makers and other industries that make wireless devices.

Smart meters are already saving ratepayers money, Carroll said. Roughly 98 percent of billing information now is being transmitted over the meters, eliminating the need for 50,000 meter reader visits during the last eight months of 2012. By contrast, spending a year on a debate at the PUC is a waste of ratepayer money, he said.

"They should be debating this with the FCC," Carroll said. "Is Maine the place to have the debate over those standards "
In the last two months, utility regulators in Texas and Vermont also have made public a study on the health effects of smart meters. The Vermont study found the highest level of exposure to be 3.9 percent of the FCC's safety limit. In Texas, a review of scientific research by the PUC staff found "no credible evidence" to suggest that advanced meters emit emissions in harmful amounts.